Current measurement apparatus

Abstract

A tracking current is separated easily. A current measurement apparatus 10 according to the present disclosure is configured to measure a tracking current. The current measurement apparatus 10 includes a magnetic core 11 that can be disposed so as to enclose wiring 100 to be measured, and first and second coils L1 and L2 wound on the magnetic core 11. The number of turns of the second coil L2 is smaller than that of the first coil L1. The second coil L2 is configured to be able to detect the tracking current flowing through the wiring 100.

1 . A current measurement apparatus configured to measure a tracking current, the current measurement apparatus comprising:
 a magnetic core that can be disposed so as to enclose wiring to be measured; and   first and second coils wound on the magnetic core,   wherein   the number of turns of the second coil is smaller than the number of turns of the first coil, and   the second coil is configured to be able to detect the tracking current flowing through the wiring.   
     
     
         2 . The current measurement apparatus according to  claim 1 , wherein the first coil is configured to be able to detect a commercial power frequency current flowing through the wiring. 
     
     
         3 . The current measurement apparatus according to  claim 2 , further comprising:
 a first current measurement circuit configured to measure the commercial power frequency current detected by the first coil; and   a second current measurement circuit configured to measure the tracking current detected by the second coil.   
     
     
         4 . The current measurement apparatus according to  claim 3 , further comprising:
 a controller; and   a display,   wherein the controller is configured to control the display to display the commercial power frequency current measured by the first current measurement circuit and the tracking current measured by the second current measurement circuit.   
     
     
         5 . The current measurement apparatus according to  claim 1 , further comprising:
 an amplifier circuit configured to amplify an output current of the second coil; and   a low-pass filter configured to output a commercial power frequency current, among an output current of the amplifier circuit,   wherein an output current of the low-pass filter is fed back to the first coil.   
     
     
         6 . The current measurement apparatus according to  claim 5 , further comprising:
 a first current measurement circuit configured to measure the output current of the low-pass filter; and   a second current measurement circuit configured to measure the tracking current detected by the second coil.   
     
     
         7 . The current measurement apparatus according to  claim 6 , further comprising:
 a controller; and   a display,   wherein the controller is configured to control the display to display the output current of the low-pass filter measured by the first current measurement circuit and the tracking current measured by the second current measurement circuit.   
     
     
         8 . The current measurement apparatus according to  claim 5 , wherein the second coil is configured to be able to detect the commercial power frequency current, as well as the tracking current. 
     
     
         9 . The current measurement apparatus according to  claim 1 , wherein the number of turns of the second coil is equal to or smaller than 1/100 of the number of turns of the first coil. 
     
     
         10 . The current measurement apparatus according to  claim 1 , wherein the magnetic core is configured in shape of a ring. 
     
     
         11 . The current measurement apparatus according to  claim 1 , wherein the magnetic core is configured to be partly openable and closable.